- Buyers Guide
Military Microwaves Supplement
Recent Advances in Radar Technology
Using Calibration to Optimize Performance in Crucial Measurements
Galileo Moves Forward
The European Galileo satellite navigation system moved a step nearer to reality with a January 2003 industry day designed to cover applications to join and invest in the Galileo joint undertaking that will develop and manage the capability. Designed to provide Europe with an independent but complimentary capability to America's Global Positioning System (GPS), the Galileo project has been beset by arguments over programme leadership and has provoked considerable hostility in the US where it is seen as both a threat to American dominance in the field and as unnecessary duplication. Assuming all goes to plan, 2003 will see interested parties competing for a satellite construction contract which should be awarded during the following year. As set out earlier in 2002, it is hoped to inaugurate the Galileo service (with a constellation of 30 satellites) on 1 January 2008.
According to usually reliable sources, Galileo will provide five types of user service including an encrypted public regulated service format that is designed for use by police forces and emergency services such as coast guards. As such, the facility is reported as being planned to provide 6.5 m positional accuracy in the horizontal plane and 100 ns accuracy in the time domain. Alongside its standard L-band (1 to 2 GHz) output, the Galileo system is also being billed as incorporating an ultra high frequency (UHF - 300 MHz to 3 GHz) relay channel for search and rescue activities. System revenue generation is expected to come from a 1/ 2 levy on the sale of chipsets for use in its receivers, a revenue stream that is predicted as generating 50 M in 2010 and an annual figure of 500 M by 2020.
As noted earlier, Europe sees Galileo as a compliment to GPS and expects it to provide a more robust, available and accurate service when operating in conjunction with the American system than is currently available. Although not intended specifically for military use, there can be little doubt that the availability of such an independent capability will be eagerly taken up by a number of armed forces across the continent.
BAE Systems Reveals Fast Jet CWS...
International contractor BAE Systems has revealed that it is proceeding to full-scale development of a collision warning system (CWS) for use on military fast jet aircraft. Designed to reduce the incidence of near misses and mid-air accidents, the new system is described as making use of secondary surveillance radar techniques, with the host aircraft carrying an interrogator that transmits Mode A and C interrogation signals. Functionally, a received response is used to generate range and bearing data, with that for range being determined via the delay time between transmission and reception. Bearing is established using the monopulse technique and is derived by measuring either the phase or amplitude differential between the transmitted and received signal at spatially separated receiver antenna elements. Taking these values together with a calculated range rate, the CWS uses the Tau criteria (range divided by range rate) to assess the likelihood of an impending collision. A positive calculation activates a voice warning message that is outputted to the host aircraft's crew headsets. An associated situational awareness unit can also be used to visually display target tracks together with their interrogator and height codes. BAE Systems further notes that the described equipment specifically addresses the problems associated with low level flight and utilises specially developed algorithms to minimise multipath effects, thereby reducing the number of false alarms generated. In more detail, the described CWS transmits on a spot frequency of 1030 MHz (with a 10 W peak output) and receives on a spot frequency of 1090 MHz. Range is given as being eight nautical miles, with the ability to handle closing speeds of better than 1000 knots. Azimuth and elevation coverages are given as ±60° and better than -10° to +20°. The system's bearing accuracy is noted as being ±15°.
...and Completes Ptarmigan Out-of-area Upgrade
BAE Systems UK-based command, control, communications, computers, intelligence, surveillance and reconnaissance (C4ISR) business unit has announced delivery of the 30th and final Mobile Access to the Ptarmigan Packet Switching (MAPPS) hardware/software package to the UK's Ministry of Defence. Designed to enhance the data handling capacity of the existing Ptarmigan Single Channel Radio Access (Central) - SCRA(C) - battlefield communications installation, MAPPS provides a local combined circuit and packet switch that gives improved data access to mobile Ptarmigan system subscribers and enables it to be deployed independently of main Ptarmigan trunk networks in out-of-area deployments. Of the 30 MAPPS packages (the hardware for which is based on BAE Systems C4ISR's MRS 2000 product), 15 make use of donor SCRA(C) vehicle containers and pallets (installed aboard Bedford 4 ´ 4 wheeled chassis) and are designated as SCRA (Switching Central)(Standard) - SCRA(SC)(Std) - units. The remaining 15 have been installed aboard government furnished Pinzgauer all-terrain vehicles, with the choice of chassis being predicated by its air transportability. So installed, the architecture is known as the SCRA (Switching Central)(Air Portable) - SCRA(SC)(AP). Each SCRA(SC) (AP) unit comprises a two vehicle convoy, with vehicle one being designated as the primary communications container vehicle and vehicle two being used as a power generation and support platform. Launched in February 1998, the overall MAPPS programme has been expanded (starting in October 1998) to incorporate the design and installation of General Purpose Trunk Access Port (GP-TAP) software enhancements that are designed to support interoperability between UK and allied communications systems in coalition operations. GP-TAP is noted as having been successfully embodied in Germany and the UK during mid-2002.
Elisra Launches New Naval Countermeasures Suite
Israeli contractor Elisra Electronic Systems has launched a new electronic countermeasures suite that it claims is suitable for installation aboard any type of naval vessel. Designated as the NS-9003A-V2/ 9005A-V2 system, the new suite functions by detecting and identifying (with a 100 percent probability of intercept) over-the-horizon radar signals, generating audio and visual threat alarms and providing an automatic, active countermeasures response. The equipment's electronic support (ES) subsystem typically comprises an array of direction-finding (DF) and omni antennas, a DF receiver unit and an inboard ES rack that houses an operator station (with colour display), an ES computer, a main processor unit and a power distribution unit. Frequency and signal bearing are measured on a pulse-by-pulse basis across the 1 to 18 GHz frequency band (extendable to 0.5 to 40 GHz if required) and the architecture is configured to intercept and analyse exotic signal types including chirp, frequency hopping and staggered pulse repetition frequency (PRF) configurations.
For its part, a typical configuration for the suite's 8 to 20 GHz band active countermeasure subsystem comprises port and starboard transmission arrays, a multibeam array transmitter, a high voltage power supply, a cooling unit and an inboard electronics rack. Alongside its primary platform defence role, the NS-9003A-V2/9005A-V2 suite is also reported as being able to provide an electronic intelligence capability that includes PRF and scan pattern analysis together with emitter video display and data recording facilities.
Functionally, the NS-9003A-V2/9005A-V2 system is billed as being fully interoperable with other onboard systems such as decoy launchers, hard-kill weapons, fire-control systems and radars. Suite control is by means of the ES subsystem's operator station or via the host vessel's command system, with the suite-vessel communications medium being a local area network. Aside from the cited frequency band coverages, system specifications include a frequency resolution of 2 MHz, a DF accuracy of 2° RMS, a sensitivity of -65 dBm to -75 dBm, and dynamic and pulsewidth ranges of > 60 dB and 0.05 µs to continuous wave, respectively.
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